Flabellate grasshopper (Melanoplus occidentalis)
| Melanoplus occidentalis | |
|---|---|
 | |
| Other common names | |
| Occidental grasshopper | |
| Taxonomic classification | |
| Suborder: | Caelifera |
| Family: | Acrididae |
| Subfamily: | Melanoplinae |
| Tribe: | Melanoplini |
| Genus: | Melanoplus |
| Scientific name | |
| Melanoplus occidentalis (Thomas, 1872) | |
| Geography | |
| Native countries: | |
| Pest status | |
| Known pest | |
The flabellate grasshopper (Melanoplus occidentalis), also known as the occidental grasshopper, is a colorful species found in open grasslands across western North America. It feeds on a variety of plants, generally preferring broadleaf plants to grasses, and produces one generation per year. Although usually a minor component of grasshopper communities, it can contribute to mixed-species outbreaks and cause crop or forage losses, particularly during drought.
Taxonomy
For full nomenclature and taxonomic details of this taxon, see Orthoptera Species File
No subspecies recorded for this taxon.
Mitochondrial DNA analyses recovered Melanoplus occidentalis and M. confusus as sister species among the species sampled, despite their placement in separate morphology-based species groups.[1] An expanded analysis using four mitochondrial genes supported this relationship, with 83% bootstrap support.[2]
Identification
Spur-throated grasshoppers are a diverse group in the family Acrididae, distinguished by a spur on the underside of the body near the front legs. They generally have thread-like antennae, and their wings and flight abilities vary widely, from wingless species to strong-flying bird grasshoppers in the genus Schistocerca. They do not produce the flight sounds or stridulation characteristic of some other grasshopper groups.[3]
This small to medium-sized species is among the most colorful members of the genus Melanoplus, with a bright orange inner surface on each hind femur and light blue hind tibiae.[4] The body is reddish-brown, darker on top and yellowish underneath. A dark stripe runs along the top of the head and may continue onto the shield-like area just behind it, which also has a dark stripe or patch on each side. The dark front wings reach the end of the abdomen or slightly beyond it, with alternating light and dark, roughly square spots along the middle. The thick upper sections of the back legs are dark with pale diagonal bands, while the slender lower sections are light blue.[3]
Identification details
Nymphs develop through five instars and are brightly patterned in gray, tan, or green, with a pale gray underside. The face is nearly vertical and uniformly tan or green, although the frontal costa may be darker. The antennae are threadlike, and the compound eyes are spotted, with a diagonal dark brown line near the middle of the posterior half. A prominent cream-colored crescent extends from the cheek below each eye onto the lateral lobe of the pronotum. Each hind femur has a dark brown stripe that is completely interrupted at three points.[5][6]
The pale gray underside helps distinguish nymphs of the flabellate grasshopper from the otherwise similar M. infantilis, whose underside is usually white, and M. gladstoni, whose underside is typically bright yellow. Seasonal timing provides another useful clue: M. occidentalis and M. infantilis nymphs occur early in the season alongside M. sanguinipes and M. packardii. M. gladstoni nymphs appear later, when the other four species are adults.[6]
M. occidentalis adults are brightly colored. The body is reddish-brown to gray, with dark brown mottling, bright orange patches, and a light brown underside. The most useful identifying features are the bright orange lower and inner surfaces of the hind femora, light blue hind tibiae, and a V-shaped dark brown patch in the middle of the inner surface of each hind femur.[6] A dark brown median stripe extends from between the eyes to the back of the head, widening toward the rear sometimes continuing onto the pronotum.[3] Viewed from above, the posterior margin of the pronotum forms a rounded right angle. A black patch occurs on the upper portion of the anterior half of each lateral lobe. The forewings are slender, tapered, and brown, with a narrow yellow stripe along the middle and patterned with square, dark spots. They reach the tip of the abdomen or extend slightly beyond it, while the hind wings are colorless. The hind femora also show variable patterns of oblique pale patches on a dark background, or the reverse.
Additional terminal features include very small, triangular furculae and a small, cone-shaped projection just below the apical edge of the subgenital plate.[3][5]
The male cercus is unusually large and especially distinctive, described as triangular, ear-like, or fan-shaped; this fan-like form gives the species its common name, “flabellate.”[3][6] Males measure approximately 18 mm in length, and females about 25 mm.[3]
Closely related species, particularly in Melanoplus and Schistocerca, can be difficult to differentiate.[3] The Nevada sage grasshopper (Melanoplus rugglesi) is a closely related species that occurs in California, the northwestern United States, and neighboring parts of Canada. Males can be distinguished by the shape of their cerci: those of the Nevada sage grasshopper are somewhat rectangular rather than triangular, with tips that do not narrow to a single point as in the flabellate grasshopper.[3]
Identification resources
| Title | Author(s) | Year | Geographic purview | URL |
|---|---|---|---|---|
| Common Grasshoppers of Montana Cropland and Rangeland | Montana State University | View URL | ||
| A Manual of the Grasshoppers of New Mexico | New Mexico Cooperative Extension Service,D.B. Richman, D.C. Lightfoot, C.A. Sutherland and DJ. Ferguson | 1993 | View URL | |
| Orthoptera of Northern Great Plains | North Dakota State University | 2007 | ||
| The grasshoppers of Nebraska | Animal and Plant Health Inspection Service,Mathew L. Brust, Wyatt Hoback and Robert J. Wright | 2009 | View URL | |
| Common Wyoming pest grasshoppers | University of Wyoming,Scott Schell and Alexandre Latchininsky,B.A. Shambaugh | View URL | ||
| Montana.gov Orthoptera Field Guides | View URL | |||
| Field Guide to Common Western Grasshoppers | United States Department of Agriculture,Robert E. Pfadt | 2002 | ||
| Grasshoppers of the Western United States | United States Department of Agriculture | View URL | ||
| ARS grasshopper species fact sheets | Agricultural Research Services and United States Department of Agriculture | 1994 | ||
| Pest Grasshoppers of the West | University of Wyoming | 2005 | View URL | |
| The Grasshoppers of the Western U.S. Lucid mobile app | APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture and Center for Plant Health Science and Technology of the USDA | 2016 | ||
| Rangeland Grasshopper Management | University of Wyoming,Jeffrey Lockwood and Scott Schell | 1993 |
Distribution
The flabellate grasshopper occurs throughout much of the western Great Plains and Rocky Mountain region, ranging from southern Canada, British Columbia to Saskatchewan, to northern Mexico. [3][7]
Biology and ecology
Found in open grasslands, including high-elevation pastures, this species feeds on both grasses and broadleaf plants, with a preference for the latter.[3][5][8]
Common in eastern Wyoming’s prairies but rare in the desert Southwest. It reportedly favors mixedgrass prairie, although it also thrives in Wyoming’s shortgrass prairie.[9]
Diet / Feeding ecology
A polyphagous species that feeds on a variety of plants but favors forbs. Preferred food plants include scarlet globemallow, western wheatgrass, and sida; it also consumes bahia, blue grama, and threeawn.[5] and refs with
In southeastern Wyoming, flabellate grasshoppers have been observed feeding on the stamens of plains prickly pear (Opuntia polyacantha). Individuals gathered in the flowers and fed in bouts lasting approximately 10–15 minutes, sometimes interrupted by aggressive encounters with other grasshoppers. Females were especially common in cactus patches.[10]
The species also occasionally consumes dying or dead arthropods.[6]
Population ecology
Flabellate grasshopper populations fluctuate over time. In a favorable Wyoming mixedgrass prairie habitat, adult densities ranged from 0.1 to 7.3 per square yard over 10 years, remaining below one per square yard in half of those years. The species appears absent from some mixedgrass prairie habitats, particularly in Montana.[6]
Flabellate grasshoppers are active during the day and rest on bare ground at night. About 45 minutes after sunrise, they turn sideways to the sun and bask for roughly two hours before moving, feeding, and laying eggs, when air temperatures reach about 70°F and soil temperatures reach 90–100°F. During midsummer heat, when air temperatures reach 90°F and soil temperatures reach 130°F, adults retreat to shade on small shrubs, 3–6 inches above the ground. They resume activity as temperatures drop in late afternoon, bask again about two hours before sunset, and settle on the ground for the night as sunlight fades.[6]
Reproduction / Life history
Eggs begin hatching relatively early in the season, around mid-spring, and adults are present from June through October.[3] Flabellate grasshopper eggs hatch around the same time as those of the bigheaded, striped, and spottedwinged grasshoppers that occur alongside it. Hatching takes place over approximately 25 days.[6] The flabellate grasshopper passes through five nymphal stages and reaches adulthood in 40–45 days, developing at roughly the same rate as the bigheaded grasshopper. As in most grasshopper species, males mature before females.[6]
Adults remain in the mixedgrass prairie habitat where they developed, feeding on green host plants and reproducing. Mating occurs mainly in the morning, sometimes as early as 30 minutes after sunrise. Females lay their first clutch about two weeks after becoming adults, depositing 8–10 eggs in two columns, ½–1 inch deep in bare soil. The egg pod is about 1 inch long, with eggs in the curved lower half and dried froth above. Females continue laying throughout their short lives, but their total egg production is unknown. The species produces one generation per year.[6] M. occidentalis eggs are yellow, averaging 5.31 mm in length and 1.24 mm in diameter.[5]
Management
The flabellate grasshopper can contribute to mixed-species outbreaks, damaging crops and reducing forage for livestock, particularly during drought. Management generally targets the broader grasshopper community, using insecticide treatments that balance effective control with reduced costs and environmental impacts.
Pest status
Rarely reaches outbreak densities on its own but can contribute substantially to outbreaks involving other pest species. It is common in prairie grasshopper communities and can damage crops and/or compete with livestock for grazing under drought conditions[5][6][4][7]
Outbreaks
Outbreak media coverage
Management methods
The main strategy for managing grasshopper outbreaks on rangelands in the United States involves the use of insecticides applied via all-terrain vehicle (ATV)-mounted or aerial sprayers. Recommended insecticides include diflubenzuron, malathion, chlorantraniliprole, various pyrethroids, and carbaryl. Applications are made either through full-area coverage or using a method known as Reduced Agent and Area Treatments (RAATs). RAATs are an integrated pest management (IPM) technique where insecticide rates are lowered from standard levels, and treated swaths are alternated with untreated ones, reducing total coverage to 50% or less. This method combines direct chemical control (killing grasshoppers in treated areas and as they migrate from untreated zones) with conservation biological control, allowing natural enemies in untreated areas to help suppress the population. This IPM strategy can cut both insecticide use and treatment costs by more than half. Control efforts typically achieve around 80% effectiveness, which is adequate to suppress most grasshopper populations. The insect growth regulator diflubenzuron has shown particular success in RAAT applications due to its long-lasting residual toxicity, which persists for about three weeks.[11][12][13]
Land-use change
Organizations associated with the species
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Projects
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Featured resource
Resources
| Title | Author(s) | Year | Geographic purview | URL |
|---|---|---|---|---|
| Common Grasshoppers of Montana Cropland and Rangeland | Montana State University | View URL | ||
| A Manual of the Grasshoppers of New Mexico | New Mexico Cooperative Extension Service,D.B. Richman, D.C. Lightfoot, C.A. Sutherland and DJ. Ferguson | 1993 | View URL | |
| Orthoptera of Northern Great Plains | North Dakota State University | 2007 | ||
| The grasshoppers of Nebraska | Animal and Plant Health Inspection Service,Mathew L. Brust, Wyatt Hoback and Robert J. Wright | 2009 | View URL | |
| Common Wyoming pest grasshoppers | University of Wyoming,Scott Schell and Alexandre Latchininsky,B.A. Shambaugh | View URL | ||
| Montana.gov Orthoptera Field Guides | View URL | |||
| Field Guide to Common Western Grasshoppers | United States Department of Agriculture,Robert E. Pfadt | 2002 | ||
| Grasshoppers of the Western United States | United States Department of Agriculture | View URL | ||
| ARS grasshopper species fact sheets | Agricultural Research Services and United States Department of Agriculture | 1994 | ||
| Pest Grasshoppers of the West | University of Wyoming | 2005 | View URL | |
| The Grasshoppers of the Western U.S. Lucid mobile app | APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture and Center for Plant Health Science and Technology of the USDA | 2016 | ||
| Rangeland Grasshopper Management | University of Wyoming,Jeffrey Lockwood and Scott Schell | 1993 |
References
Specimen contributors for this species
Bionomia links specimen records in GBIF to the people who collected and identified them. Each list shows the top 20 for this species.
Identified by
People who determined the taxonomic identity of specimens of this species.
- Tyler Grant — 8 specimens identified
References
- ↑ Chapco W, Kuperus WR, Litzenberger G (1999) Molecular phylogeny of melanopline grasshoppers (Orthoptera: Acrididae): The genus Melanoplus. Annals of the Entomological Society of America 92(5): 617–623. https://doi.org/10.1093/aesa/92.5.617academic.oup
- ↑ Chapco W, Litzenberger G (2002) A molecular phylogenetic analysis of the grasshopper genus Melanoplus Stål (Orthoptera: Acrididae)—an update. Journal of Orthoptera Research 11(1): 1–9. https://doi.org/10.1665/1082-6467(2002)011[0001:AMPAOT]2.0.CO;2
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 Capinera JL, Scott RD, Walker TJ (2004) Field guide to grasshoppers, katydids, and crickets of the United States. Cornell University Press, Ithaca, New York, 280 pp. ISBN 978-0-8014-8948-8.cornellpress.cornell+1
- ↑ 4.0 4.1 Montana Natural Heritage Program (n.d.) Occidental grasshopper—Melanoplus occidentalis. Montana Field Guide. https://fieldguide.mt.gov/speciesDetail.aspx?elcode=IIORT01H60 (accessed 9 Oct. 2026).
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Capinera JL, Sechrist TS (1982) Grasshoppers of Colorado: Identification, biology, and management. Bulletin 584S. Colorado State University Experiment Station, Fort Collins, Colorado, 161 pp. https://hopperwiki.org/images/4/48/Grasshoppers_(Acrididae)_of_Colorado-_identification,_biology_and_management.pdf
- ↑ 6.00 6.01 6.02 6.03 6.04 6.05 6.06 6.07 6.08 6.09 6.10 Pfadt RE (1994) Flabellate grasshopper (‘’Melanoplus occidentalis’’). Wyoming Agricultural Experiment Station Bulletin 912. Species Fact Sheet. https://www.ars.usda.gov/ARSUserFiles/30320505/grasshopper/Extras/PDFs/Species%20Fact%20Sheets/Flabella.pdf
- ↑ 7.0 7.1 Vickery VR, Kevan DKMcE (1985) The grasshoppers, crickets and related insects of Canada and adjacent regions. The insects and arachnids of Canada, Part 14. Publication 1777. Research Branch, Agriculture Canada, Ottawa, Ontario, 918 pp. https://publications.gc.ca/collections/collection_2016/aac-aafc/agrhist/A42-42-1985-14-eng.pdf
- ↑ Hebard M (1928) The Orthoptera of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia 80: 211–306. https://www.jstor.org/stable/4063996
- ↑ University of Wyoming (n.d.) Flabellate grasshopper—Melanoplus occidentalis. Wyoming Grasshopper Distribution Atlas. Grasshoppers of Wyoming and the West. https://www.uwyo.edu/entomology/grasshoppers/wy-distribution-atlas/melanoplus-occidentalis.html
- ↑ Lockwood JA, Bomar CR (1992) Consumption of prickly pear cactus flowers by Melanoplus occidentalis: A coevolutionary association? Environmental Entomology 21(6): 1301–1307. https://doi.org/10.1093/ee/21.6.1301
- ↑ Latchininsky A (2019) In: Lecoq M, Zhang L (Eds) Encyclopedia of pest Orthoptera of the world. China Agricultural University Press, Beijing, China, pp. 9, 23, 53, 136, 141, 145, 151.
- ↑ Latchininsky AV, Schell SP (2007) Aerial RAATs brochure. ATV-RAATs brochure. UW CES Bulletin MP-95, Laramie, WY, USA.https://hopperwiki.org/index.php/UWYO_information_on_reduced_agent_and_area_treatments_(RAATs)
- ↑ Lockwood JA, Schell SP (1997) Decreasing economic and environmental costs through reduced area and agent insecticide treatments (RAATs) for the control of rangeland grasshoppers: empirical results and their implications for pest management. Journal of Orthoptera Research 6: 19–32.